The Ultraviolet Extinction Curve for Circumstellar Dust Formed in the Hydrogen‐poor Environment of V348 Sagittarii

1997 ◽  
Vol 476 (2) ◽  
pp. 865-869 ◽  
Author(s):  
John S. Drilling ◽  
James H. Hecht ◽  
Geoffrey C. Clayton ◽  
Janet Akyuz Mattei ◽  
Arlo U. Landolt ◽  
...  
1970 ◽  
Vol 36 ◽  
pp. 139-139
Author(s):  
Kenneth L. Hallam

Ultraviolet stellar fluxes from 1500 to 3200 Å were from February through August 1965 on OSO II. A 15-cm diameter Gregorian telescope with a stepped grating spectrophotometer provided flux measurements in ten adjacent 180 Å wide band passes.By comparing fluxes of stars showing B-U color excesses smaller than 0.19 and larger than 0.26, an ultraviolet extinction curve has been derived, which agrees with others which have been published as far as the magnitude effect is concerned, but the shape differs somewhat, the slope at 1/λ = 3.8 μ−1 being somewhat greater than at 1/λ = 5.0 μ−1.If the stars' fluxes are corrected for reddening, it is found that there is a good agreement between observation and models for stars earlier than B3, but that many of the later type stars have a residual apparently intrinsic reddening.


2002 ◽  
Vol 566 (1) ◽  
pp. 267-275 ◽  
Author(s):  
T. P. Sasseen ◽  
M. Hurwitz ◽  
W. V. Dixon ◽  
S. Airieau

2004 ◽  
Vol 602 (1) ◽  
pp. 291-297 ◽  
Author(s):  
D. C. B. Whittet ◽  
S. S. Shenoy ◽  
Geoffrey C. Clayton ◽  
Karl D. Gordon

2020 ◽  
Vol 72 (6) ◽  
Author(s):  
Mudumba Parthasarathy ◽  
Tadafumi Matsuno ◽  
Wako Aoki

Abstract From Gaia DR2 data of eight high-velocity hot post-AGB candidates, LS 3593, LSE 148, LS 5107, HD 172324, HD 214539, LS IV −12 111, LS III +52 24, and LS 3099, we found that six of them have accurate parallaxes which made it possible to derive their distances, absolute visual magnitudes (MV) and luminosity (log L/L⊙). All the stars except LS 5107 have an accurate effective temperature (Teff) in the literature. Some of these stars are metal poor, and some of them do not have circumstellar dust shells. In the past, the distances of some stars were estimated to be 6 kpc, which we find to be incorrect. The accurate Gaia DR2 parallaxes show that they are relatively nearby, post-AGB stars. When compared with post-AGB evolutionary tracks we find their initial masses to be in the range 1 M⊙ to 2 M⊙. We find the luminosity of LSE 148 to be significantly lower than that of post-AGB stars, suggesting that this is a post-horizontal-branch star or post-early-AGB star. LS 3593 and LS 5107 are new high-velocity hot post-AGB stars from Gaia DR2.


1970 ◽  
Vol 39 ◽  
pp. 322-335
Author(s):  
H. C. van de Hulst

The material of this Discussion has been rearranged in five sections: 1. Grain Orientation; 2. The Diffuse Galactic Light; 3. The Extinction Curve in the Far UV; 4. Formation and Destruction of Grains; 5. The OH Molecule. Except for rearranging, very few changes have been made.


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